1. Field of the Invention
The present invention relates to a heterogeneous network in which a macro cell and a small-scale cell co-exist, and more particularly, to a method and terminal for measuring an interference.
2. Related Art
A 3rd generation partnership project (3GPP) long term evolution (LTE) that improves a universal mobile telecommunications system (UMTS) has been introduced to a 3GPP release 8. The 3GPP LTE uses an orthogonal frequency division multiple access (OFDMA) in a downlink and a single carrier-frequency division multiple access (SC-FDMA) in an uplink. The OFDM needs to know in order to understand the OFDMA. The OFDM may be used since an inter-symbol interference effect can be reduced due to low complexity. The OFDM converts data to be input in serial into N parallel data and transmits it by carrying N orthogonal sub-carriers. The sub-carriers maintains orthogonally in a frequency dimension. Meanwhile, the OFDMA means a multiple access method to realize multiple accesses by providing a part of the available sub-carrier to each user independently, in a system using the OFDM in a modulation scheme.
In recent years, there is an ongoing discussion on 3GPP LTE-advanced (LTE-A) evolved from the 3GPP LTE.
In addition, recently, there is ongoing discussion on a heterogeneous network in which a macro cell and a small-scale cell co-exist. In particular, there is an ongoing discussion for traffic offloading by distributing terminals having access to the macro cell to the small-scale cell.
When the macro cell and the small-scale cell transmit a channel state information (CSI)-reference signal (RS) in a coordinated manner in such a heterogeneous network, a terminal must feed back a channel quality indicator (CQI) both in a normal subframe and an almost blank subframe (ABS). The CQI may be calculated through an interference measurement. The interference measurement must be performed in both of the ABS subframe and the normal subframe. However, there is a case where the interference is not measured on the ABS subframe according to a situation.